(a) Field of the Invention
The present invention relates to a converter and a driving method thereof.
(b) Description of the Related Art
A converter is a circuit that converts an input voltage to a desired output voltage. Such a converter is mounted to various electronic devices a power supply.
The converter includes various types of converters, such as a boost converter, a buck converter, a flyback converter, and the like. Among them, an active clamp flyback converter has been widely used in applications that require a wide range of an input voltage and high power density.
The active clamp flyback converter further includes a clamp switch in addition to a main switch, and further includes an additional clamp capacitor. When the main switch is turned off, the clamp switch is turned on. Such an active clamp flyback converter can easily realize zero voltage switching using the clamp switch and the clamp capacitor. In a typical flyback converter, a voltage overshoot occurs due to leakage inductance of a transformer and a parasitic capacitance of the main switch at turn-off of the main switch, and a snubber circuit is used to eliminate the voltage overshoot. The active clamp flyback converter can prevent the voltage overshoot using turning-on of the clamp switch and the clamp capacitor at turn-off of the main switch without using the snubber circuit.
However, such an active clamp flyback converter has a high conduction loss, and accordingly it may not be appropriate to an application that requires ultra-high power density, like a mobile communication terminal.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.